1)
Ans :
In my last class I was learned about Linked list, stack and queue.

2)
Ans :
Data Structure can be defined as the collection of data objects which provides a way of storing and managing data in the computer so that it can be used. Various Data Structures types are arrays, Linked List, Stack, Queue, etc. Data Structures are widely used in almost every aspect of Computer Science for simple as well as complex computations. Data structures are used in all areas of computer science such as Artificial Intelligence, graphics, Operating system etc.

3)
Ans :

A data structure is a particular way of organizing data in a computer so that it can be used effectively. In this article, the real-time applications of all the data structures are discussed.

Stack :
Some Applications of a stack are:
1.Converting infix to postfix expressions.
2.Undo operation is also carried out through stacks.
3.Syntaxes in languages are parsed using stacks.
4.It is used in many virtual machines like JVM.

Queue :
Some applications of a queue are:
1.Operating System uses queue for job scheduling.
2.To handle congestion in networking queue can be used.
3.Data packets in communication are arranged in queue format.

Graph :

Some applications of a graph are:
1.Facebook’s Graph API uses the structure of Graphs.
2.Google’s Knowledge Graph also has to do something with Graph.
3.Dijkstra algorithm or the shortest path first algorithm also uses graph structure to finding the smallest path between the nodes of the graph.

Tree :
Some applications of the trees are:
1.XML Parser uses tree algorithms.
2.Decision-based algorithm is used in machine learning which works upon the algorithm of tree.
3.Databases also uses tree data structures for indexing.
4.Domain Name Server(DNS) also uses tree structures.